The Pediatric Drug Surveillance ("PeDS") Program is an epidemiologic study of the clinical effects of drugs in hospitalized children. It was established on selected wards of the Children's Hospital Medical Center over two years ago, and has proven to be an effective system for the collection, storage, and retrieval of clinical information from these wards. We now propose to expand the current effort to include intensive care newborn nurseries, cardiology and neurology wards, and pediatric wards in community hospitals not closely affiliated with a medical school. The objectives of this study include 1) the detection of previously unsuspected adverse drug effects in these populations, 2) the evaluation of patient factors that may influence the outcome of drug therapy, 3) the development of the capability for evaluating drugs not yet approved for use in certain age groups, ("orphan drugs"), 4) the development of a monitoring approach that can facilitate the conduct and analysis of clinical trials of various drugs and therapies in children, and 5) comparison between referral and community hospital pediatric wards of both the methods and findings of an intensive surveillance program. For the newborn population, we will 6) develop methods for obtaining, recording, and analyzing information relating to maternal characteristics (including exposure to drugs and other environmental agents) as they affect the infant, 7) design and apply statistical methods for understanding the effects of drugs on growth and growth-related variables and the effects of these variables on other outcomes of drug therapy, and 8) develop a system of record linkage whereby information gathered by the PeDS Program will be linked to outcome data derived from an ongoing infant follow-up program that will provide information on the long-term effects of drugs in these patients. A trained nurse-monitor will be stationed on each of the proposed wards and will systematically collect detailed clinical information on patients admitted consecutively to the monitored wards. These data include general medical characteristics, details of all drug exposures, and descriptions of various outcomes during the hospital admission. The data are reviewed and entered onto magnetic tape for various analyses.